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Home > Products > Integrated Circuits (ICs) > Clock/Timing > Application Specific Clock/Timing

Diodes Incorporated PI6C557-03BLEX

Name: PI6C557-03BLEX
Brand: Diodes Incorporated
SKU: PI6C557-03BLEX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PI6C557-03BLEX

Manufacturer:: Diodes Incorporated

Category:: Application Specific Clock/Timing

Package:: 16-TSSOP (0.173", 4.40mm Width)

Datasheet:: PI6C557-03BLEX.pdf

Description:: IC CLOCK GENERATOR 16TSSOP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

PI6C557-03BLEX from Diodes Incorporated is a PCIe 3.0-compliant spread spectrum clock generator with two HCSL differential outputs, 3.3V supply, 25MHz crystal input, and selectable output frequencies (25/100/125/200MHz) for EMI reduction in PC and embedded host systems.

For engineers reviewing the PI6C557-03BLEX datasheet, PI6C557-03BLEX pinout, PI6C557-03BLEX application, or PI6C557-03BLEX equivalent, key selection criteria include PCIe 3.0 phase jitter (0.45ps RMS), HCSL current-mode drive (0.8V, 6×IREF), spread-spectrum control via SS0/SS1 pins, and industrial temperature operation (−40°C to +85°C).

Technical Context

The PI6C557-03BLEX implements a proprietary PLL architecture optimized for PCIe 3.0 timing compliance, accepting only a 25MHz fundamental-mode crystal or single-ended clock input and generating two independent HCSL differential clock pairs at 25/100/125/200MHz via S0/S1 configuration pins.

Spread spectrum modulation is digitally controlled via SS0/SS1 pins with three modes: no spread, −0.5%, or −0.75% down-spread at 30–33kHz; output enable (OE) provides tri-state control with 10μs enable/disable timing, and IREF pin sets output current via external 475Ω resistor for 50Ω trace termination.

Key Specifications

Parameter	Value and Actual Design Meaning
PCIe 3.0 Phase Jitter	0.45ps RMS (high-frequency band); meets PCIe 3.0 specification for reference clock stability
Output Frequency Options	25MHz, 100MHz, 125MHz, 200MHz; selected by S0/S1 logic pins per Table 1
HCSL Output Drive	0.8V current-mode differential pair; requires external 33Ω series + 49.9Ω ground termination per PCIe layout guidelines
Supply Voltage	3.3V ±10%; supports standard PCIe system rail with 95mA typical operating current
Spread Spectrum Modes	−0.5%, −0.75%, or no spread; selected by SS0/SS1 pins with 3ms settling time after change
Cycle-to-Cycle Jitter	35ps (typ); ensures timing margin for high-speed serial link sampling windows
Operating Temperature	−40°C to +85°C; qualified for industrial-grade motherboard and server board deployment

Pinout & Package

PI6C557-03BLEX is packaged in a 16-pin TSSOP (173mil wide, L-code), RoHS-compliant and lead-free, with exposed pad not present. Pin functions are validated per Diodes DS45359 Rev 1-2.

Pin/Terminal	Circuit Role	Design Meaning
1, 2 (S0, S1)	Frequency select inputs	Binary-coded selection of 25/100/125/200MHz output; internal pull-up enables default 25MHz on floating
3, 8 (SS0, SS1)	Spread select inputs	Two-bit encoding for no spread, −0.5%, or −0.75% down-spread; internal pull-up defaults to no spread
4 (X1/CLK), 5 (X2)	Crystal/clock interface	X1/CLK accepts 25MHz crystal or CMOS clock; X2 is crystal output-leave open for clock input mode
6 (OE)	Output enable	Active-low control; pulls all CLK outputs to high-impedance when LOW (10μs disable time)
9 (IREF)	Current reference output	Connects to 475Ω resistor to set 2.32mA reference; output current = 6×IREF for 50Ω HCSL drive
10, 11, 14, 15 (CLK1, CLK1, CLK0, CLK0)	Differential HCSL outputs	Complementary pairs for two independent clocks; require external series and termination resistors per PCIe layout rules
12, 16 (VDDA, VDDX)	Analog & crystal power	Separate 3.3V supplies decoupled with 0.01μF capacitors; improves PSRR and jitter performance
7 (GNDX), 13 (GNDA)	Crytal & analog ground	Isolated ground returns minimize noise coupling between crystal oscillator and output drivers

Key Features

Feature	Design Value
PCIe 3.0-compliant jitter performance	0.45ps RMS high-frequency phase jitter ensures reliable Gen3 link training and BER <10⁻¹²
Configurable spread spectrum	Hardware-selectable −0.5%/−0.75% down-spread reduces EMI peak amplitude without firmware or register writes
HCSL-compatible differential outputs	Current-mode 0.8V outputs meet PCIe 3.0 HCSL electrical specs and support direct connection to Gen3 root complex/endpoint receivers
Dual independent clock channels	Two fully buffered, isolated HCSL pairs enable simultaneous clocking of CPU and PCIe switch or dual-slot configurations
Industrial temperature range	−40°C to +85°C operation supports deployment in unventilated embedded systems and edge servers

Applications

PCIe Root Complex Clocking

Embedded GPU Interface Timing

Use Scenario: Providing primary reference clock to CPU PCIe controller and chipset in industrial motherboards.

IC Role / Device Role / Timing Role: PCIe 3.0-compliant clock generator delivering 100MHz HCSL differential clock to root complex PHY layer.

Use Value: 0.45ps RMS jitter ensures robust link negotiation and stable 8GT/s data rates under thermal stress.

Use Scenario: Driving PCIe 3.0 lanes connecting SoC to discrete GPU in ruggedized edge AI systems.

IC Role / Device Role / Timing Role: Dual-output clock source supplying synchronized 100MHz clocks to GPU upstream/downstream interfaces.

Use Value: Independent HCSL pairs eliminate inter-channel skew (<50ps), preserving lane alignment across multi-lane x16 links.

Server Backplane Clock Distribution

PCIe Switch Fanout Timing

Use Scenario: Generating low-jitter reference clocks for multiple PCIe slots on 1U/2U rackmount server backplanes.

IC Role / Device Role / Timing Role: EMI-reduced clock source with −0.75% spread enabling compliant emissions in dense metal chassis environments.

Use Value: Hardware-controlled spread eliminates need for software configuration, simplifying BIOS/firmware bring-up.

Use Scenario: Feeding clock inputs of PCIe 3.0 switches (e.g., Broadcom PEX87xx) in storage and networking appliances.

IC Role / Device Role / Timing Role: Low-skew, high-drive clock buffer with OE control enabling dynamic power gating during link idle states.

Use Value: 10μs OE response allows rapid clock shutdown during ASPM L1 substates, reducing system standby power.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PCIe 3.0 clock generator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
IDT 9DB403D	3-output LVDS/HCSL generator; higher integration but fixed 100MHz output; no spread control	Requires external spread modulator for EMI reduction; lacks hardware SS0/SS1 pins	Choose when multi-output count >2 is required and spread is managed externally
ON Semi NB3N502	Single 100MHz HCSL output; no spread spectrum; lower jitter (0.35ps RMS) but no frequency selection	Limited to fixed 100MHz; no S0/S1 programmability or dual-channel capability	Choose for cost-sensitive single-clock applications where spread is unnecessary

Compared with IDT 9DB403D and ON Semi NB3N502, PI6C557-03BLEX uniquely combines dual HCSL outputs, hardware-selectable spread, and quad-frequency flexibility in a single 16-pin TSSOP-enabling compact, firmware-free PCIe 3.0 clocking with EMI mitigation.

Availability

PI6C557-03BLEX is available at Aetrix Electronics and suitable for PCIe 3.0 root complex clocking, embedded GPU interface timing, and server backplane clock distribution requiring stable component supply and industrial temperature operation.

Supply support for PI6C557-03BLEX includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and integrated circuits, specializing in high-performance analog, logic, and timing solutions for computing, industrial, and communications markets.

The PI6C557 product line delivers PCIe-compliant clock generators focused on EMI reduction and layout simplicity in space-constrained host platforms-designed specifically for motherboard, server, and embedded PCIe infrastructure.

FAQ

What crystal specifications are required for stable operation?

The PI6C557-03BLEX requires a 25MHz fundamental-mode parallel-resonant crystal with ≤300ppm frequency tolerance over −40°C to +85°C and load capacitance of 18pF. Diodes recommends GC2500003 or FL2500047 crystals; external load capacitors must be set to (CL − 8) × 2 = 16pF for CL = 18pF.

How is HCSL output termination implemented on the PCB?

HCSL outputs require a 33Ω series resistor per CLK line and a 49.9Ω resistor to ground on each complementary pair, placed within 0.2 inches of the PI6C557-03BLEX pins. Differential routing must use 100Ω coupled microstrip/stripline traces with strict length matching per PCIe Layout Guidelines.

Can the device operate in LVDS mode?

Yes-the PI6C557-03BLEX supports LVDS-compatible voltage levels when configured with RP = RQ = 100Ω and RT = 150Ω terminations per the LVDS Layout Guidelines. Output swing adjusts automatically; no internal register change is needed-only external resistor reconfiguration.

What is the function of the IREF pin and how is it used?

IREF is a precision current reference output that sinks 2.32mA when a 475Ω resistor connects it to ground. This sets the internal current source such that each HCSL output delivers 6 × IREF = ~13.9mA into 50Ω loads, ensuring correct 0.8V common-mode and differential swing per PCIe HCSL spec.

PI6C557-03BLEX Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: 16-TSSOP (0.173", 4.40mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Programmable:: Not Verified

PLL:: Yes

Main Purpose:: Ethernet, PCI Express (PCIe)

Input:: HCSL, Crystal

Output:: HCSL, LVDS

Number of Circuits:: 1

Ratio - Input:Output:: 1:2

Differential - Input:Output:: No/Yes

Frequency - Max:: 200MHz

Voltage - Supply:: 3V ~ 3.6V

Operating Temperature:: -40°C ~ 85°C

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

Supplier Device Package:: 16-TSSOP

PI6C557-03BLEX FAQ

1.How can I place an order for PI6C557-03BLEX through Aetrix?

Please submit a Request for Quotation (RFQ) for PI6C557-03BLEX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for PI6C557-03BLEX reliable?

The price and inventory of PI6C557-03BLEX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PI6C557-03BLEX is usually 5 days.

3.What payment methods are accepted for PI6C557-03BLEX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PI6C557-03BLEX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PI6C557-03BLEX?

PI6C557-03BLEX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PI6C557-03BLEX order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for PI6C557-03BLEX?

For technical support, including PI6C557-03BLEX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PI6C557-03BLEX requirements.

6.How does Aetrix verify that PI6C557-03BLEX is sourced from the original manufacturer or authorized distributors?

All PI6C557-03BLEX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PI6C557-03BLEX meets industry standards.

7.What is the process for return or replacement of PI6C557-03BLEX?

All PI6C557-03BLEX units undergo pre-shipment inspection (PSI). If there is an issue with PI6C557-03BLEX, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The PI6C557-03BLEX part is unused and in its original packaging.

Return procedure for PI6C557-03BLEX:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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